Field of Invention
The present invention relates to laser optical systems for head lamps, and, more particularly, to a laser optical system for a head lamp, in which, among light outputted from a laser diode, light incident on a fluorescent body and then scattered backwards is incident on the fluorescent body again to obtain an additional quantity of light and thereby increase light efficiency.
Description of Related Art
A head lamp (headlight) of a vehicle is a lamp that lights the front area of a vehicle so as to secure a driver's clear view. The head lamp generally uses halogen, High Intensity Discharge (HID), and a LED diode as a light source.
However, halogen, HID, and LED diode technologies are problematic in that they are high in power consumption, so that they are low in light efficiency. Further, halogen, HID, and LED diode technologies are problematic in that an entire size of an optical system including a light source and a lens is large, so that the degree of freedom in design is low and weight is heavy.
Recently, there is being developed a head lamp using a laser diode as a light source that is environment-friendly and has a long life and high light efficiency.
As shown in FIG. 1, the conventional laser optical system for the head lamp includes a laser diode 1 which generates laser beams of a blue wavelength range, a PCB substrate 2 to which the laser diode 1 is attached and which controls the supply of current to the laser diode 1, a fluorescent body 3 which reacts with light outputted from the laser diode 1 to output white light, a housing 4 which has a guide path 4a guiding light, outputted from the laser diode 1, to the fluorescent body 3, and a cover 5 which is coupled to the housing 4 to fix the fluorescent body 3.
Among light that is outputted from the laser diode 1 and then is incident on the fluorescent body 3, some light may be scattered backwards as shown by the arrows indicated by dashed lines. However, the conventional laser optical system of FIG. 1 is problematic in that it is impossible for the backwardly scattered light to be incident on the fluorescent body 3 again, so that an optical loss is caused and light efficiency is deteriorated.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.